composing for solo cello

Hi, I am in urgent need of some advice about composing for solo violoncello. I am in a foreign country and have three days to compose a solo cello accompaniment to a vocal track. I have some ideas in mind and would be really grateful of help in order to realise them. Firstly I want to know what is the name for style of playing where the bow glides across the 4 strings playing broken chords lightly / sometimes can sound 'scratchy'? Does it have a name? How do you write it? How difficult